The change synchronization is done via synchronized blocks on the AnimatorBase instance.
Status get / set activity is synced with a RecursiveLock, used as a memory barrier.
This is suitable, since all change requests are allowed to be expensive
as they are not expected to be called at every frame.

setUpdateFPSFrames

frames - Update interval in frames. At every rendered frames interval the currentTime and fps values are updated.
If the frames interval is <= 0, no update will be issued, ie the FPSCounter feature is turned off. You may choose FPSCounter.DEFAULT_FRAMES_PER_INTERVAL.

out - optional print stream where the fps values gets printed if not null at every frames interval